The present invention is directed to a plurality of coulter units mounted on an agricultural tool bar, and wherein each coulter unit includes an upstanding shank secured to a tool bar, and about which each coulter is capable of pivoting for seedbed preparation. Numerous arrangements of this general type are shown in prior art U.S. Pat. Nos. 4,574,891 to Williamson; 4,656,957 to Williamson et al; 4,745,978 to Williamson; 4,759,411 to Williamson; 4,947,770 to Johnston and 4,987,841 to Rawson et al. None of these prior art structures disclose the features of the present invention.